iommu/iova: Put free_iova_mem() outside of spinlock iova_rbtree_lock

It is not necessary to put free_iova_mem() inside of spinlock/unlock
iova_rbtree_lock which only leads to more completion for the spinlock.
It has a small promote on the performance after the change. And also
rename private_free_iova() as remove_iova() because the function will not
free iova after that change.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/1620647582-194621-1-git-send-email-chenxiang66@hisilicon.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/iova.c

@@ -412,12 +412,11 @@ private_find_iova(struct iova_domain *iovad, unsigned long pfn)
 	return NULL;
 }
 
-static void private_free_iova(struct iova_domain *iovad, struct iova *iova)
+static void remove_iova(struct iova_domain *iovad, struct iova *iova)
 {
 	assert_spin_locked(&iovad->iova_rbtree_lock);
 	__cached_rbnode_delete_update(iovad, iova);
 	rb_erase(&iova->node, &iovad->rbroot);
-	free_iova_mem(iova);
 }
 
 /**
@@ -452,8 +451,9 @@ __free_iova(struct iova_domain *iovad, struct iova *iova)
 	unsigned long flags;
 
 	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
-	private_free_iova(iovad, iova);
+	remove_iova(iovad, iova);
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+	free_iova_mem(iova);
 }
 EXPORT_SYMBOL_GPL(__free_iova);
 
@@ -472,10 +472,13 @@ free_iova(struct iova_domain *iovad, unsigned long pfn)
 
 	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
 	iova = private_find_iova(iovad, pfn);
-	if (iova)
-		private_free_iova(iovad, iova);
+	if (!iova) {
+		spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+		return;
+	}
+	remove_iova(iovad, iova);
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
-
+	free_iova_mem(iova);
 }
 EXPORT_SYMBOL_GPL(free_iova);
 
@@ -825,7 +828,8 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad)
 		if (WARN_ON(!iova))
 			continue;
 
-		private_free_iova(iovad, iova);
+		remove_iova(iovad, iova);
+		free_iova_mem(iova);
 	}
 
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);